Lawn Care Guide

Indicator Plants: Trees Prone To Diseases and Insects

Indicator plants are a tree or shrub commonly found in landscapes in the area that often experiences a specific problem that will cause serious damage to the plant if left untreated.

The list of indicator plants for an area does not include all of the common trees and shrubs in that area because most plants in the landscape are not likely to experience a problem that will cause serious damage. Therefore, from the standpoint of their long-term health and vigor, Spring-Green Tree and Shrub Care Service is particularly beneficial to indicator plants.

Learn what types of indicator plants are in the East, Midwest, Pacific Northwest and South regions of the United States.

Indicator Plants in the United States

crabapple tree indicator plantsCrabapple Trees

There are about 1,500 varieties of Crabapples, but most are smaller, wide and full trees. They commonly flower extensively in the spring, with a variety of colors. Its leaves are small and simple in shape, reddish-brown to green in color. The bark on Crabapples is also reddish-brown and fairly smooth.

In the East, Midwest and Pacific Northwest, Crabapple indicator plants are prone to Scab disease, Cedar Apple Rust Disease Tent Caterpillars, Caterpillars and Aphids.

maple tree indicator plantsMaple Trees

From a distance, Maple trees are found in several different varieties, most of which are very common residential trees. They are categorized by one of two major group’s: hard maple or soft maple. Soft maples are less desirable, but are faster growing. Hard maple leaves are large, dark green leaves with mild lobe points. Soft maple leaves are a much lighter green, with sharp, deeply lobed patterns.

The bark on hard maples have a smooth bark when young, but become coarse and somewhat vertically furrowed in texture. The soft maple bark is much lighter in color and remains much smoother. Generally very thin, the soft maple’s bark tends to crack vertically under growth and temperature stresses.

During winter, Silver maples can be recognized by their smooth, light gray bark. The bark will occasionally crack or peal in vertical strips. Hard maples have a much more coarse, fissured bark texture.

In the East, Midwest, and South Maple indicator plants are prone to Caterpillars, Leafminers, Aphids, Leaf Scorch, Anthracnose and Borers.

White Birch Trees

White Birch medium-sized trees are most distinguishable by their white, smooth bark. Growth can be erratic and random in branching. Its leaves are small, somewhat heart- shaped, with saw-tooth edges.

The bark is smooth and easily identified, sometimes giving rise to its name, “paper birch”. White Birch trees are very easy to recognize in the winter because of its white, paper-like bark. In the East, Midwest and Pacific Northwest, White Birch indicator plants are prone to Aphids, Leafminers, and Chlorosis,

Ash Trees

Ash trees Indicator plantsWhile many types of Ash trees exist, the green and white types are most common. A common structural characteristic of Ash trees can be the downward curving growth of their lower branches. Leaves are arranged as a series of leaflets, 6 or 8 leaflets to a leaf, with one growing perpendicular on the end; generally dark green in color.

The bark is medium rough texture and light gray in color. The main stems have deep, diamond-shaped furrows in vertical patterns. Secondary and other small branches are much smoother in texture, and are yellowish in color.

In the East and Midwest, Ash indicator plants are prone to Aphids and Borers.

Although these trees are prone to disease or insects, that does not mean you should avoid planting them. These types of trees are a wonderful feature to any home or landscape.

Your local neighborhood lawn care professional will be able to provide recommendations to properly care for your trees, and offer a 2-Step Tree Program to help supply the tree with nutrients that enhance the health of your ornamental plants.